There have a been a couple of dual atomizer devices that have reached the market. Tesla CP Couples as an example. Not sure how successful they were, seems more of gimmick to test the waters - but the trend has never caught on. That said, all (at least from what I have seen) have been dual cell devices that have incorporated a regulated circuit per battery with perhaps a feature that allows only one circuit to be utilized when a single atomizer is in use. I’m making a guess at that so don’t quote me on it.
@degnr8 – not to discourage your project, but that would be a bit of a challenge to pull off correctly. Battery discharge in a regulated device is dependent on the prescribed wattage. Wattage should not exceed the batteries CDR limits, which becomes even more limiting if utilizing a single cell. By using 2 atomizers that require to be fired at the same time, you are effectively increasing coil mass which will require and equal amount of additional power to heat both those coils efficiently. If the coils are identical across both atomizers, and your required wattage does not exceed the battery CDR limits, then a single circuit could pull this off. But if the coils are not identical, then you need to be able to adjust power independently per coil. Again, while keeping total combined wattage below the batteries CDR limits.
What are you trying to achieve with firing 2 different atomizers at the same time?